Just Breathe
by Masher L
Summary: Mikasa and Armin had a one-night stand. It doesn't really affect anything- until Mikasa starts showing signs of pregnancy. (Rated M for lemon) mainly ArminxMikasa
1. Chapter 1

**A/N: So, this is my first SNK fanfic so cut me some slack, alright? Basically, this first chapter is a lemon—my first of those too! So no flames, please! Constructive criticism is welcome, though!**

**DISCLAIMER: I do not own **_**Attack on Titan**_** or any of its characters. I only own the plotline of this story. **

Chapter 1

Mikasa sighed. "It's just so weird, you know?" she said, "When I'm around Eren, I just… my hands get clammy, I can't breathe, and I feel so… nervous. You know?"

Armin looked up. "It actually kind of sounds like you maybe… have a crush on him?"

Mikasa blushed. "N-no! That's just… that's just…"

Armin shrugged. "I mean, it _is_ pretty obvious that you like him, actually…"

Mikasa covered her face in embarrassment.

"I won't tell anyone," Armin said.

Mikasa still felt embarrassed. She looked up, still blushing, and said, "Can I… can I do something?"

Armin just nodded and said, "Sure,"

Then Mikasa kissed him. Armin at first widened his eyes in surprise, then closed his eyes and kissed her back.

Mikasa ran her hand through his hair. Everything inside him told him to stop, but he couldn't.

She broke the kiss and looked in his eyes.

"What- what are we doing?" Armin asked, blushing furiously.

Mikasa backed away. "Sorry. I just… sorry…"

Armin, still blushing, said, "Don't- don't worry about it…"

Mikasa sat down on the couch. "You know," she said, "You're not that bad of a kisser,"

"Neither are you," Armin mumbled.

Next thing they knew, they were kissing again. Mikasa pulled Armin on top of her. She started unbuttoning his pants. Armin was too caught up in the moment to care. He started unbuttoning Mikasa's shirt.

Armin started undoing Mikasa's belt when she got his pants off him.

Armin pulled away a little. "Are you sure you want to do this?"

Mikasa nodded. "Yeah,"

"I just…" Armin scratched the back of his head. "I've never done this before."

"Me neither," Mikasa sighed.

"So, do I just…?"

"You might want to take your boxers off first," she snickered.

"Oh," Armin chuckled. "Yeah." He pulled his boxers off.

Mikasa sighed. "Just… be gentle…" she said.

Armin nodded and went in, gently.

"Mmrgh!" Mikasa dug her nails into his skin. She bled a little.

Armin backed off. "You okay?"

Mikasa panted. "I just… need to get used to it…"

Armin nodded then went in again. Mikasa gasped a little bit, but quickly adjusted.

"Faster," she breathed.

Armin went faster. He moaned a little bit.

Mikasa whispered in his ear, "You're so cute when you moan," then nibbled on it.

Mikasa moaned when she had an orgasm, and Armin gasped when he ejaculated into her.

They laid on the floor, covered by a blanket, panting. Mikasa put her hand against her head. "That was…"

Armin finished her sentence. "…amazing…"

Mikasa looked at him. "Yeah," she kissed his cheek and sat up. She started getting dressed again.

Armin put his shirt back on. Mikasa looked at him.

"You don't think you got me pregnant just now… do you…?"

Armin shook his head. "Hardly ever happens on the first time.

Mikasa nodded and pulled her trousers on.


	2. Chapter 2

**A/N: Okay, awkward lemon out of the way, let's get to the real story :D**

Chapter 2

Armin violently bit into a loaf of bread at breakfast. He was nervous. _I slept with Mikasa… I slept with Mikasa! Why did I do that?!_

Eren sat down across from him. He tilted his head. "You okay?"

Armin looked up. "I-I'm f-fine…" he said.

Mikasa sat down next to Eren. "Hey, guys," she said.

While this happened, Hanji and Levi sat at a nearby table. Hanji heard a little bit of what was going on and said to Levi, "Sounds like something interesting is going on here."

Corporal Levi looked up, his eyebrows furrowed as always, and listened as well.

Eren looked at Armin. "Okay, you're acting weird."

"S-sorry…" Armin said.

Mikasa bit her lower lip and looked at Armin.

Hanji stood up and put her hand on Armin's shoulder. "Well, if I didn't know any better, I'd say you had a one-night stand!" She laughed.

Armin stood up and said, "Talk to you guys later," and left.

Hanji raised her eyebrows. "Son of a bitch!" she muttered.

xxx

Armin buried himself under the sheets of his bed. He tried to sleep, but he felt guilty for what happened the previous night.

Meanwhile, Mikasa sat in her room, twiddling her thumbs. Eren was in the room with her.

"What do you think that was about?" Eren said, "You don't think he _actually _had a one-night stand, do you?"

Mikasa stood up. "Hold on a minute." She ran to the bathroom and vomited in the toilet.

"Mikasa!" Eren said, "Are you okay?"

Mikasa wiped her mouth. "I'm fine," she said before vomiting again.

"Doesn't sound like it," Eren said.

"I just… ate something bad… I think that's it…" She stood up and wiped her mouth with a towel.

xxx

"Hanji, don't bother," Levi said just as the scientist was about to knock on Armin's door.

"But why would _Armin _do what I think he did?" Hanji said.

"He probably didn't," Levi said.

"Well, we may never know!" Hanji knocked on the door.

"It's open!" Armin yelled.

Hanji opened the door and slammed it in Levi's face.

"Hey, kiddo," she said. "You okay?"

"I'm fine," Armin said from under the covers.

"You've been acting strange…" Hanji said.

"It's… it's nothing…" Armin turned his back to her.

"Come on, kiddo," she nudged him. "What is it?"

At that moment, Mikasa knocked on the door.

"It's open!" Armin yelled again.

Mikasa walked in. "Hey, I was just gonna ask—oh, hello, commander," she said, "Um, may I please have a moment with Armin?"

"Um, yeah, of course," Hanji stood up and walked out of the room.

"Hey, Mikasa," Armin said, "What is it?"

"Well, after breakfast I kind of… threw up… a little… is that normal after… you know…?"

Armin sat up. "I-I wouldn't think so…" He started to look concerned. "But… would morning sickness even happen the morning after?"

"I'm not sure," Mikasa said, "That's why I asked you."

"Okay, well," Armin looked around and sighed. "I… probably wouldn't worry about it… right now, at least…"

"O-okay," Mikasa nodded. "You feeling okay?"

"I'm fine. Really. I guess it's just the after effect," Armin shrugged.

"Well, okay, um… I'll see you in training, then?"

"Yep,"

**A/N: I think y'all know what's coming next xD**


	3. Chapter 3

**A/N: Alright, so this chapter takes place about a month later. Enjoy :D**

Chapter 3: A Month Later

It was lunch time in the Survey Corps headquarters. Armin sat down across from Eren and Mikasa, like he usually did. Sasha was devouring a shit load of food, as usual, but what threw him off is when Mikasa finished her food first.

After swallowing her last bite, she said, "Ugh. I'm still hungry."

Eren laughed a little bit. "You ate more than Sasha could!"

Sasha looked up. "Shut up!" Then she bit into a potato.

Mikasa nudged Eren in the rib. "Yeah, shut up."

Armin raised his eyebrows. "M-Mikasa?"

"What?" she looked at Armin.

Armin gulped and said, "Never mind…"

Mikasa rolled her eyes.

xxx

Mikasa was throwing up in the toilet again. She was throwing up in the morning constantly. It wasn't until she noticed herself gaining weight that she began to worry.

In the middle of the night, Mikasa knocked on Armin's door.

Armin sat up. "It's open…" he said.

Mikasa came in. "Armin?"

"M-Mikasa?" Armin said, "What is it?"

"Armin," Mikasa said again. "I think I'm pregnant…"

Armin rubbed his eyes. "Huh?"

"I think I'm pregnant," she repeated. "I've been throwing up in the morning a lot, and I… I missed my period…"

Armin just looked at her, and then stood up. "Shouldn't you go get checked?"

"Yeah…"

xxx

The next morning, Mikasa knocked on the door to Hanji's lab.

Hanji opened the door. "Hey, Mikasa. What do you need?"

Mikasa invited herself in and said, "Well, about a month ago, I… I had sex with someone and I wanted to make sure I'm not, you know, pregnant…"

Hanji looked at her. She was silent for a moment, then said, "Let me go get something." She went to the back for a moment, then came back with a small cup. "This might be an odd request, but could you… um, pee in this cup? That's usually how pregnancy tests are done, so…"

"A-alright," Mikasa took the cup and went to the bathroom. She came back holding the cup with her index finger and her thumb.

"Wait here, okay?" Hanji said.

Mikasa nodded.

After a few minutes, Hanji came back with the results. "Uhm…" she said, "Sorry to say, but… yes… you are pregnant…"

Mikasa widened her eyes. "What?" she said. "I'm… I'm pregnant?" She had tears in her eyes.

Hanji handed her some tissues. "I know it's not what you wanted to hear…" she said.

Mikasa took a few tissues and said, "Well, um, I… might as well tell him…"

"Tell who? The father?" Hanji said.

Mikasa sniffled. "Yeah,"

Hanji looked at her. "I mean, if you're comfortable… could you tell me who it is?"

Mikasa shook her head. "I just… I need to clear my head before I do anything else. Thank you," Mikasa stood up and left the room.

She went to her room and covered herself with her blankets. She tried not to cry, but eventually she was sobbing.

Eren walked by her room and heard the crying. He knocked on the door. "Mikasa?"

"Go away!" Mikasa yelled.

Eren was shocked at this response, since she was usually always by his side. "It's me, Eren. Are you okay?"

"No. Go away."

Eren tilted his head. Armin walked by and said, "Is everything okay?"

Eren shrugged.

Armin said, "I'm gonna see what's up." Then he walked in. He looked at Eren. "Just give us a minute."

Armin came and sat at the side of Mikasa's bed. "Hey," he said.

Mikasa looked at him. "Hey,"

"You okay?"

"No," Mikasa said.

"Did you get…?"

Mikasa started tearing up again. "Armin, I'm pregnant." She sniffled.

Armin raised his eyebrows. "Mikasa… I… I'm so, _so _sorry…" He started tearing up, too.

Mikasa sat up and hugged him while crying.

"Armin," she said. "What do I do? What do _we _do? What if we go on another expedition? What if I… can't go?"

"We'll figure it out when that happens," Armin said.

xxx

The next day, Armin sat where he usually did with Mikasa and Eren.

Mikasa ate like a pig. Eren looked at her.

"God," Eren said, "Why are you eating so much? Are you trying to imitate Sasha?"

Sasha glared at him.

Mikasa nudged Eren in the rib.

"Oww…" Eren said, clutching his rib.

Armin looked at her. "Mikasa…"

Mikasa looked at him and glared. She then stood up and walked away.

"…I'm gonna go follow her," Eren said, standing.

So Armin sat alone, nibbling on bread.

xxx

Eren chased after her. "Mikasa!" he said.

Mikasa turned around. "What?"

Eren put his hands on her shoulders. Mikasa widened her eyes and tried not to blush.

"What the hell is going on with you? And don't tell me nothing, because I know better than that." Eren looked in her eyes.

Mikasa sighed. "Um… well…" She backed away. "I need to tell you… in private…"

"Oh… okay…"

They went to Mikasa's room. Mikasa paced for a moment, then looked at Eren.

"What is it?" Eren said.

Mikasa sighed, then mumbled.

"Mikasa, I can't hear you—"

"I'm pregnant!" Mikasa said finally. "I'm pregnant, okay? I made a huge mistake and I'm facing the consequences, alright?"

Eren picked up his jaw. "H-how—?"

"It was mostly my fault, Eren; I seduced him…"

Eren came closer. "Who, exactly, is 'him'?"

Mikasa sighed. "I'll… tell you that part later, okay?"

"No, I want to know now," Eren said.

"Well, too bad!" Mikasa yelled. "Because I'm not telling you!"

Eren sighed. "Then I'll figure it out!" he said, leaving and slamming the door behind him.

Meanwhile, Armin was laying in his bed, thinking hard when Eren knocked on his door.

Armin sat up. "Come in!" he yelled.

Eren came in and said, "Did you know Mikasa was pregnant?"

Armin sat up. "No," he said, "I didn't."

"And she's refusing to tell me who the father is!" Eren sat next to him. "I swear to God, I will kill the bastard who—"

"Eren, it was me," Armin said.

Eren looked at him, wide eyed. "W-what?!"


	4. Chapter 4

**A/N: SHIT BE GETTING REAL**

Chapter 4

Eren looked at Armin, eyes widened. "But… what… why… how…!"

Armin raised his hands defensively. "I don't know, Eren, but—"

Eren punched him. Hard. Enough to make Armin's nose making a cracking sound.

Armin laid there on the ground, huddled in a ball. His nose was bleeding.

Eren stood there for a minute and looked at him, then kicked him in the stomach.

Armin coughed.

Someone rushed into the room. "Eren! What the hell!" It was Mikasa. Eren was about to strike Armin again when she grabbed him by the back of his shirt and threw him against the wall.

"Okay, look, Eren. Yes, Armin is the father of my child. But that doesn't mean you can kill him!" Mikasa was _pissed_.

_Is she actually standing up for me? _Armin wondered, trying to look up.

Mikasa said, "Get out. I need to talk to Armin."

Eren stood, looking down, and left the room.

Mikasa sighed. "I can't believe he did that." She knelt down by Armin. "Armin," she said.

Armin was shaking. Blood was dripping onto the floor from his nose.

Mikasa helped him onto the bed and got a tissue to stop the blood. Armin held his right eye and groaned.

"So you told him, huh?" Mikasa said.

Armin just nodded.

Mikasa sighed. "He didn't need to do that, though. That's why I wasn't gonna tell him. I thought if he heard it from you he'd take it differently, but I guess not." She touched the hand that was over his eye. "Let me see…"

Armin uncovered his eye, revealing the forming bruise around it.

Mikasa furrowed her eyebrows. "Son of a bitch…"

"S-sorry…" Armin said.

"I'm not mad at you, Armin… I'm mad at Eren. He shouldn't have done this to you." Mikasa said.

"But we wouldn't even be having this problem if it wasn't for—"

"I'm mostly at fault for that," Mikasa said. "I shouldn't have tried to seduce—"

There was a knock on the door. "What's going on in there?" It was Levi.

"Nothing, Corporal," Mikasa yelled.

"I want you down in the mess hall in thirty minutes. I have to discuss something with all of you."

"Okay!" Mikasa said. She helped Armin up and got a wet rag to put over his eye and a tissue for his nose. Then they went down to the mess hall.


	5. Chapter 5

A/N: Levi is a difficult character to write, so don't throw flames at me if I don't get him exactly right.

Chapter 5

Armin sat at a table near the far end of the mess hall. He held a wet rag over his eye and a tissue over his nose.

Levi narrowed his eyes. "The hell happened to you?"

"N-nothing…" Armin said.

Levi turned and walked to the front of the room. He started speaking.

"I have this… letter from Commander Erwin," he said, opening the letter. "There is an expedition in a month. He has a specific list of people he wants to go, but anyone else is welcome to join. Those required to go are…" He turned a page. "Armin, Mikasa, Eren…" He said other names, but Armin tuned them out.

Mikasa can't go, Armin thought. What if she gets eaten? Then the baby would—

"Mikasa can't go," Eren said.

Mikasa glared at him. "Yes I can!"

"No, you can't,"

Mikasa put her hands around his throat. "Yes. I. Can!"

"Enough!" Levi yelled.

Mikasa dropped Eren.

"I want you two and Arlert to meet me in my office. And you better have a damn good explanation why you would choke one of your friends."

Mikasa stormed off to her room, and Eren stormed off to his. Armin went to Levi's office.

Levi sat in his chair. "Sit," he said.

Armin sat down in the chair in front of Levi's desk.

Levi looked at him. "Who did that to you?" he said, pointing at his face.

"Actually, I, um… I fell," Armin said.

"You're not a very good liar, Armin," he said. He asked the question again: "Who did that to you?"

Armin looked down and said, "Eren did, sir,"

Levi raised an eyebrow. "What exactly happened?"

"Well, um," Armin kept looking down.

"Well, um, what?"

He mumbled something.

"What?" Levi said.

"Eren was mad at me because I got Mikasa pregnant."

Levi choked on his tea a little. "What?"

"Please don't make me say it again, sir," Armin said.

"No, I heard you. Just… what?" Levi looked at him.

Armin looked down. "Sorry, sir,"

Levi shifted his head around a little bit. "Thank you for talking to me… you can go now…"

Armin quickly left the room.

xxx

Mikasa had her back turned to Eren in Levi's office. She was still pissed off at him.

Levi, still recovering from the shock at what Armin said, said, "Mikasa… why did you choke Eren?"

"It's the only way he'll shut up," she said coldly.

Okay, so she is pregnant, Levi determined when she had spoken so coldly about Eren.

"Levi," Eren said, "Mikasa's—"

"Don't you dare!" Mikasa interrupted.

"It's okay," Levi said, "I already know about the kid,"

Mikasa looked at him. "But… how?"

"These walls are thin," Levi said, "I've heard things.

"So, I'm writing a letter to Erwin to ask about it."

"But— but sir—!"

"I won't mention you directly," Levi said, "but I need to know if it's safe for you to go,"

Mikasa sighed. "Fine. Can I go now?"

"Yes, both of you are dismissed."

xxx

Armin was asleep when Mikasa barged into his room.

"Armin?"

He opened his eyes a little. "Yeah?"

Mikasa came closer. "I can't sleep,"

Armin sat up. "Why not?"

"I don't know." She sat on Armin's bed and leaned her head against his shoulder.

"Is Eren still mad at me?" Armin asked.

"I yelled at him for a little bit, and he agreed not to kill you," Mikasa said.

Armin shrugged. "Good enough,"

Mikasa closed her eyes. "I'm not ready for this,"

Armin didn't say anything, just nodded and sighed.


	6. Chapter 6

Chapter 6

Truth was, Eren was not happy about Mikasa being pregnant. But the first reason above all: he was jealous.

_Why did she go to Armin and not me that night? _Eren pondered.

Meanwhile, Mikasa was in her bedroom, waiting for them to be called down to the mess hall. She looked in the mirror and noticed a small bump forming near her belly. It wouldn't be obvious to the others unless she pointed it out, so she was safe for now.

Someone knocked on the door. Mikasa opened it. "Hey, Armin,"

"Hey," Armin said. "Just checking in on you. Making sure you're doing okay."

"I have a bump," Mikasa said, "Everyone's gonna see."

"I didn't even notice until you pointed it out," Armin said. "No one will notice. It's not something most people are looking for."

"Okay…" Mikasa said.

They went to breakfast and ate in silence. Eren looked at Armin with slight anger and jealousy.

"Armin," he said, "Can I talk to you for a minute?"

"If you need to talk about anything," Mikasa said, "You can say it right here."

"I just…" Eren scratched the back of his head, "I just wanted to apologize for what happened…"

"It's fine," Armin said, "I understand why you got upset."

Eren turned to Mikasa. "Can I talk to you?"

"Yeah, sure," Mikasa and Eren walked out of the room and stood in the hall.

"What is it, Eren?" Mikasa said.

Eren kissed her. Mikasa was taken aback by this, but couldn't bring herself to pull away.

Armin was watching. He was going to tell them to clean up their stuff, but stopped when he saw them kissing. He walked away before either of them could notice him.

xxx

Armin started to question what he felt for Mikasa. After seeing her and Eren kissing, he was… _jealous_? No, he couldn't be jealous. He knew jealously was a secondary emotion, usually preceded by sadness or anger or something else.

Armin thought he ought to be happy for Mikasa— she's liked Eren for so long, and now she had him.

_But I thought that night changed it…_

It was horrible for him to think such things, but it was true.

xxx

Mikasa pulled away. "Eren…"

"I waited too long, didn't I?" Eren said, "I love you, Mikasa. I have for a long time. I'm sorry I didn't say it sooner…"

"I…" She was still stunned by the kiss. "I… I'm just confused right now… I thought I loved you, too, but then…"

"I get it," Eren said.

"I just need to think things through, Eren," Mikasa started walking away. "I'm sorry."

She started walking towards Armin's room. He could help her figure this out.

xxx

Armin shot up to the knock on his door. He opened the door and said, "Mikasa…!" a little too excitedly.

She had tears in her eyes. "I don't know what to do…" she said.

Armin raised his eyebrows. "C-come in if you—"

Mikasa came into his room and sat on the bed. "I'm just so confused." She sniffled, and it became obvious to Armin that she was crying.

Armin sat down next to her. "W-what is it?"

"I love Eren," she said, "but… I love you as well…"

Armin widened his eyes. "Y-you do?"

"Yeah…" Mikasa held her head in her hands. "I just… don't know what to do. Eren's my only family, but you're the father of my child. I don't know what to do."

Armin shrugged. "Well…" He took a breath. "I'm not going to tell you what you should and shouldn't do. I just want you to be happy… more than anything."

"Ugh," Mikasa sighed. "That's what _everyone _says. It doesn't help! I need someone to actually give me a suggestion!"

Armin was a little shocked at the small outburst. "Well," Armin scratched his head. "I…"

"You what?" Mikasa said.

Armin gave her a small kiss on the lips.

Mikasa blushed. "I don't know what that means."

"I saw you and Eren kissing," Armin said.

"Oh…"

"But that's what's confusing for me," Armin stated, "because I felt something in the pit of my stomach, kind of like guilt… but it wasn't guilt. I don't really know…"

"You were jealous," Mikasa said.

"I…" Armin looked down at his feet. "I… I was?"

"Clearly," Mikasa replied. She kissed him on the lips, softly at first, then more passionately.

Armin pulled away. "Mikasa…"

"Shh," Mikasa grabbed the collar of his shirt and kissed him.

_It's the pregnancy hormones, _Armin determined. _She's not thinking clearly._

Armin pulled away again. "You're not thinking clearly right now," he said, "This isn't a good idea."

"Silly," Mikasa poked his cheek. "I'm already pregnant. I can't get pregnant again."

"But—"

Mikasa wouldn't listen. She pushed him on to the bed and started kissing him again.

xxx

Eren laid in bed, thinking through the whole situation.

_I guess it would make sense if she went for Armin, _he thought. _He is the father of her child…_

Pondering over that, he fell asleep.

**A/N: TAKING REQUESTS FOR BABY NAMES :D Just leave it in the reviews and they will all be taken into consideration ;)**


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